1. Field of the Invention
The present invention relates to vehicle wheel covers and the like and more particularly to a plastic wheel cover having clip-type retainers for securing the cover to an axial flange of a wheel.
2. Description of the Prior Art
Due to the limited design capabilities and weight of steel wheel covers, the tendency in the industry has been to utilize plastic wherever possible. Therefore, it is known to prepare wheel covers from plastic which are painted or decorated to have a desired attractive appearance. Such wheel covers are held in place by the use of a number of spring steel clip structures fitting into bosses of the plastic wheel covers. The distal ends of such clips may have cam surfaces, barbs, or tabs which may fit into recesses in the wheel structure. Several problems have arisen from the use of all plastic wheel covers. One problem is due to the heat generated in the wheels, especially on the newer front wheel driven vehicles. This problem is especially acute with disk-type brakes which tend to generate more heat than shoe-type brakes. This heat, when transmitted to the rim and to the plastic bosses of the wheel covers via the spring clips, causes distortion of the plastic and has the effect of loosening the purchase of the clips into the rim. Thus, loss of expensive wheel covers frequently occurs.
One solution of this problem is the use of improved plastics having higher melting points and greater resistance to distortion from heat. While feasible, such plastics greatly increase the cost of the wheel covers. A second problem is the tendency of the retention forces present in the spring steel clips to be transmitted to the plastic wheel covers which may not be sufficiently rigid to resist or absorb such forces. In many cases, the covers deflect or flex, thereby reducing the retention forces resulting in loss of covers. In other cases, the retention forces can cause, over an extended period of time, permanent creep or flow of the plastic with a loss in retention forces. Thus, there is a need for a plastic wheel cover and retaining clip system which can be implemented with low-cost plastic, yet will be free from the problem of distortion of the cover.